Usage

Basic usage

Encode a string in a QR code
qrtool encode "QR code" > output.png
Output
Figure 1. Generate this image
Decode a QR code from this image
$ qrtool decode output.png
QR code

Output formats

Use -t option to change the format of the generated image.

The format is

  • png (default)

  • svg

  • pic (PIC markup language)

  • ansi (to the terminal using 4-bit ANSI escape sequences)

  • ansi256 (to the terminal using 8-bit ANSI escape sequences)

  • ansi-true-color (to the terminal using 24-bit ANSI escape sequences)

  • ascii (to the terminal as ASCII string)

  • ascii-invert

  • unicode (to the terminal as UTF-8 string)

  • unicode-invert

Encode to a SVG image
qrtool encode -o output.svg -t svg "QR code"
Output
Figure 2. Generate this image
Generate a PDF file from the PIC code
qrtool encode -t pic "QR code" \
    | awk 'BEGIN { print ".vs 0\n.po 0\n.PS" } END { print "scale = 25.4 * 3\n.PE" } { print }' \
    | groff -Tpdf -p -P-p3i,3i \
    > output.pdf
Output to the terminal as UTF-8 string
qrtool encode -t unicode "QR code"

Micro QR code generation

Use --variant option to change the variant of the generated QR code. The variant is normal (default) or micro (Micro QR code).

qrtool encode -v 3 --variant micro "QR code" > output.png
Output
Figure 3. Generate this image

Colored output

Use --foreground and --background options to change the foreground and background colors of the generated image. These options takes a CSS color string such as brown, #a52a2a or rgb(165 42 42). The default foreground color is black and the background color is white of CSS’s named colors.

qrtool encode --foreground brown --background lightslategray "QR code" > output.png
Output
Figure 4. Generate this image
Colored output is also available when the output format is any ANSI escape sequences
qrtool encode -t ansi-true-color --foreground brown --background lightslategray "QR code"
Note that lossy conversion may be performed depending on the color space supported by the method to specify a color, the color depth supported by the output format, etc.

Supported input image formats

qrtool decode supports decoding a QR code from the following image formats

To support decoding from SVG image, the decode-from-svg feature must be enabled at compile time. Note that the SVG image is rasterized before scanning.

Image formats other than PNG can be disabled by disabling the default feature, and can be enabled individually.

Use -t option to specify the image format. If this option is not specified, the image format is determined based on the extension or the magic number.

Input
Figure 5. Input this WebP image
Decode a QR code from the WebP image
$ qrtool decode input.webp
QR code
# or
$ qrtool decode -t webp input.webp
QR code

Generate shell completion

--generate-completion option generates shell completions to standard output.

The following shells are supported

  • bash

  • elvish

  • fish

  • nushell

  • powershell

  • zsh

Example
qrtool --generate-completion bash > qrtool.bash

Integration with other programs

Both qrtool encode and qrtool decode can read from standard input and output to standard output.

Optimize the output image

The image output by qrtool encode is not optimized. For example, a PNG image is always output as the 32-bit RGBA format. If you want to reduce the image size or optimize the image, use an optimizer such as oxipng or svgcleaner.

Optimize the output PNG image
qrtool encode "QR code" | oxipng - > output.png
Optimize the output SVG image
qrtool encode -t svg "QR code" | svgcleaner -c - > output.svg
If the optimize-output-png feature is enabled, you can also use --optimize-png option and --zopfli option of this command to optimize output PNG image.

Reading and writing unsupported image formats

If you want to save the encoded image in an image format other than PNG or SVG, or decode an image in an unsupported image format, convert it using a converter such as ImageMagick.

Raster formats

Read Cargo.toml from standard input and save the encoded result as a XPM image
cat Cargo.toml | qrtool encode | magick png:- output.xpm
Decode this image and print the result using bat
magick output.xpm png:- | qrtool decode | bat -l toml

Vector formats

Read a string from standard input and save the encoded result as an EPS image
echo "The quick brown fox jumps over the lazy dog." \
    | qrtool encode -t svg \
    | inkscape -p -o output.eps
Decode this image and print the result to standard output
$ inkscape -o - --export-type svg output.eps | qrtool decode
The quick brown fox jumps over the lazy dog.
1. CUR is also supported.
2. SVGZ is also supported.